Hamas named Gaza Strip chief Yahya Sinwar as its new political leader on Tuesday, after his predecessor Ismail Haniyeh’s was killed in Tehran last week, sending regional tensions soaring.

“The Islamic Resistance Movement Hamas announces the selection of leader Yahya Sinwar as the head of the political bureau of the movement,” a statement from the group said.

Minutes after the announcement, Hamas’s armed wing, the Ezzedine Al-Qassam Brigades, said it fired a barrage of rockets from the Gaza Strip towards Israel.

The Israeli military and officials accuse Sinwar of being one of the masterminds of the October 7 attack on Israel, making him one of the country’s most wanted.

His appointment as the new chief of Hamas comes less than a week after Haniyeh was killed in Tehran.

Iran and Hamas have blamed Israel for his assassination. Israel has declined to comment on the killing.

Hamas’s October 7 attack resulted in the death of 1,198 people, mostly civilians, according to an AFP tally based on official Israeli figures.

During the attack, also seized 251 people, 111 of whom are still held captive in Gaza, including 39 the military says are dead.

Israel’s retaliatory military campaign in Gaza has so far killed at least 39,653 people, according to the health ministry in the Hamas-run territory, which does not provide details on civilian deaths.